BARRIER EFFECT OF DLC THIN FILMS FOR POTENTIAL APPLICATION IN BIOMEDICINE

The aim of the presented paper was the investigation of the barrier properties of Diamond Like Carbon (DLC) thin films used for biomedical applications. The DLC films were prepared by the Plasma Enhanced Chemical Vapour Deposition (PECVD) from methane. Stainless steel AISI type 316L was used as a substrate. Samples were placed on the excitation RF electrode. The self-bias ranged from -700V to -800V and the deposition time varied from 1 min to 15 min. The working gas methane pressure during process was 20 Pa. Morphology of obtained DLC layers was characterized by AFM and SEM microscopy and the coating thickness by calottes method. The surface chemical composition was identified by EDS analysis. The coated samples as well as the pure substrate were tested for leaching of allergenic nickel into environment. Physiological solution was used as a model matter for this purpose. The content of nickel in the solution was monitored using ICP-OES analysis. The obtained results proved that the barrier effect was achieved even in case of 50 nm thick DLC film.